Date of Award
M.S. in Physics
Physics and Astronomy
Joseph R. Gladden
A granular material is defined as a collection of discrete particles such as powder and grain. Granular materials display a large number of complex behaviors. In this project, the behavior of macroscopic granular materials under tornado-like vortex airflow, with varying airflow velocity, was observed and studied. The experimental system was composed of a 9.20-cm inner diameter acrylic pipe with a metal mesh bottom holding the particles, a PVC duct, and an airflow source controlled by a variable auto-transformer, and a power-meter. A fixed fan blade was attached to the duct's inner wall to create a tornado-like vortex airflow from straight flow. As the airflow velocity was increased gradually, the behavior of a set of same-diameter granular materials was observed. The observed behaviors were classified into six phases based on the macroscopic mechanical dynamics. Through this project, we gained insights on the significant parameters for a computer simulation of a similar system by Heath Rice . Comparing computationally and experimentally observed phase diagrams, we can see similar structure. The experimental observations shothe effect of initial arrangement of particles on the phase transitions.
Nishikawa, Asami, "The Behavior Of A Macroscopic Granular Material In Vortex Flow" (2014). Electronic Theses and Dissertations. 764.